The invention relates to a method and apparatus of estimating an output torque generated by an internal combustion engine.
There have been proposed various engine torque estimating methods such as a method of calculating an engine output torque on the basis of an intake air flow information A/N, and another method of measuring a pressure and a volume in a cylinder of an internal combustion engine, of providing a pressure-volume relation map by each cycle of the engine, and of calculating an engine output torque therefrom as disclosed in Japanese Patent Provisional Publication No. 4-236852. In the former method, intake air flow information A/N is an engine intake air quantity per one rotation of the engine, since A is an intake air flow rate per unit time and N is an engine speed. That is, A/N is treated as engine load information.